Strong glacial-interglacial variability in upper ocean hydrodynamics, biogeochemistry, and productivity in the southern Indian Ocean
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Nature
Date
2021-05-05Referencia bibliográfica
Tangunan, D... [et al.]. Strong glacial-interglacial variability in upper ocean hydrodynamics, biogeochemistry, and productivity in the southern Indian Ocean. Commun Earth Environ 2, 80 (2021). [https://doi.org/10.1038/s43247-021-00148-0]
Sponsorship
Universidad de Salamanca - Ministerio de Ciencia, Innovacion y Universidades Grant RTI2018-099489-B-I00; German Research Foundation (DFG) 49926684; National Science Foundation (NSF) 1737218; European Union's Horizon 2020 Research and Innovation Programme under the Marie Sklodowska Curie Grant 799531; Spanish Government CTM2017-89711-C2-1-P; European Union through FEDER fundsAbstract
In the southern Indian Ocean, the position of the subtropical front – the boundary between
colder, fresher waters to the south and warmer, saltier waters to the north – has a strong
influence on the upper ocean hydrodynamics and biogeochemistry. Here we analyse a
sedimentary record from the Agulhas Plateau, located close to the modern position of the
subtropical front and use alkenones and coccolith assemblages to reconstruct oceanographic
conditions over the past 300,000 years. We identify a strong glacial-interglacial variability in
sea surface temperature and productivity associated with subtropical front migration over the
Agulhas Plateau, as well as shorter-term high frequency variability aligned with variations in
high latitude insolation. Alkenone and coccolith abundances, in combination with diatom and
organic carbon records indicate high glacial export productivity. We conclude that the biological
pump was more efficient and strengthened during glacial periods, which could partly
account for the reported reduction in atmospheric carbon dioxide concentrations.